Elite Status for Million-Mile Fliers: Why Miles Alone May Not Be Enough

It's no secret that staying loyal to an airline carries perks, including waived baggage fees, priority boarding and first-class upgrades. And road warriors who fly upwards of one million miles on some U.S. airlines can look forward to lifetime elite status and other perks.

But changes are afoot and you might want to lock in your lifetime elite status.

The frequent-flier program landscape is altering as carriers increasingly focus on rewarding revenue and dollars spent versus miles flown. For example, beginning in 2014, Delta Air Lines will require frequent fliers to hit a minimum spend threshold in addition to miles flown to qualify for annual elite status. For example, to earn Delta's top-tier Diamond Medallion status, fliers will have to travel 125,000 miles each year and spend at least $12,500 in airline tickets.

Other major carriers, so far, haven't followed Delta's lead by adding spending requirements for elite status. Here's a look at million-miler qualifications and benefits at the three major U.S. airlines.

Delta awards million-miler status based on total Medallion Qualifying Miles (MQMs) earned during a SkyMiles member's lifetime. Unlike American, purchasing higher-priced tickets that earn bonus MQMs will get you to lifetime status faster.

After achieving one million miles, Delta provides frequent-fliers with lifetime Silver Medallion status. Perks of Silver status include priority check-in, priority boarding, unlimited complimentary upgrades and 25 percent bonus miles on every flight.

American awards million-miler status based on actual flight miles flown on American or any AAdvantage frequent-flier program partner airline. Bonus flight miles for certain higher-priced tickets such as first- and business-class aren't included in the calculation.

After achieving one million flown miles, American provides frequent-fliers with lifetime AAdvantage Gold status and 35,000 bonus miles. Perks of Gold status include priority check-in, security and boarding, as well as complimentary access to preferred seats in coach—those near the front of the cabin and enhanced legroom seats—and 25 percent bonus miles on every flight. (Read more: American Luring Frustrated United Fliers With Status Match)

At two million flown miles, AAdvantage members earn lifetime Platinum status along with four one-way systemwide upgrades that can be used for first- or business-class travel. Additional Platinum benefits above Gold-level perks include priority baggage delivery, oneworld lounge access when traveling internationally and 100 percent bonus miles on every flight.

At each additional million-mile mark, AAdvantage members receive four more one-way systemwide upgrades.

United awards million-miler status based on actual flight miles flown on United or partner Copa Airlines.

After achieving one million miles flown, United awards lifetime MileagePlus Premier Gold status to frequent-fliers. Perks of Gold status include priority check-in, boarding and security, as well as complimentary Economy Plus (enhanced legroom) seats and 50 percent bonus miles on all United and Copa flights.

At two million miles flown, MileagePlus members earn lifetime Premier Platinum status. Additional Platinum benefits above Gold-level perks include waived service fees, higher upgrade priority and 75 percent bonus miles on United and Copa flights.

At three million miles flown, United awards lifetime Premier 1K status. Additional 1K benefits above Platinum-level perks include six one-way systemwide upgrades, instant first-class upgrades on certain coach tickets and 100 percent bonus miles on United and Copa flights. (Read more: Road Warrior Tested: United Airlines International Business Class)

And at four million miles, United bestows the exclusive Global Services status, normally an invitation-only elite program providing the highest priority and benefits above other status levels.

Additionally, United allows a million-miler at any level the option to give their status to a spouse or partner living at the same address, regardless of that person's individual flying activity.